1. Field of the Invention
The present invention relates to heat exchangers used in automotive air systems. More particularly, this invention relates to heat exchangers manufactured from resin-coated members and to methods for manufacturing such heat exchangers.
2. Description of Related Art
Many of the constituent parts of known heat exchangers in automotive air systems, e.g., heat transfer members, heater cores, or the like, are made of aluminum, e.g., aluminum alloys, to facilitate heat transfer and to reduce heat exchanger weight. Such known heat exchangers comprise constituent parts made of aluminum members and may be manufactured according to the following process. A brazing filler metal is clad to a surface or surfaces of an aluminum member. The melting point of the brazing filler metal is lower than the melting point of the aluminum member. The aluminum member may be combined with other aluminum members to form a heater core of a heat exchanger. Some or all of the aluminum members may be clad with the brazing filler metal. Each aluminum member is formed and shaped. After the aluminum members are assembled, they may be heated in a furnace until the brazing filler metal melts. As a result, aluminum members constituting the core of a heat exchanger are connected together. By this method, the core of a heat exchanger may be manufactured.
In known heat exchangers used in automotive air systems manufactured as described above, the melting temperature of the brazing filler metal is at about 600° C. Therefore, the temperature of a furnace used to heat the aluminum members is increased to about 600° C. or higher.
Further, in known heat exchangers used in automotive air systems, a flux may be sprayed on the aluminum members that are to be connected using brazing filler metals to form the heat exchangers. The flux promotes the brazing connection between the aluminum members, e.g., by removing oxides from or preventing the formation of oxides on the surfaces to be joined, by facilitating the melting of the brazing filler metals, or the like. Therefore, the manufacturing cost of such heat exchangers may be increased due to the expense of providing a flux spray and due to an increase in the amount of manufacturing time needed for spraying the flux. Moreover, if the flux is sprayed unevenly or imprecisely, the connection formed between the aluminum members by brazing may be incomplete or of insufficient strength, e.g., due to the presence or formation of oxides that impede the connection of the aluminum members, by the uneven melting and flow of the brazing filler metals. Further, the heat exchangers formed by such incompletely-brazed aluminum members may have to be disposed of instead of being shipped, or they later may be recalled from the market or from customers. Moreover, repair of heat exchangers made of aluminum members that are not connected properly, e.g., due to an uneven or an imprecise flux spray, may be necessary.
In addition, in known heat exchangers used in automotive air systems, the aluminum members of some constituent parts, e.g., heater cores, may be in contact with water. As a result, corrosion preventing compounds may be clad to those aluminum members that are in contact with water. This cladding is employed to increase the resistance of the surface of these aluminum members to corrosion. As a result, the cost of the heat exchanger may increase. Further, each of the clad aluminum members of the heat exchanger may be formed by a die press. In such cases, reduced friction between the aluminum members of the heat exchanger and the die press is important in order to improve the quality of the formed aluminum members. A lubricant, e.g., lubricating oil, may be used to reduce friction and to enhance relative movement between the aluminum members and the die press. Consequently, the lubricant may be sprayed on the aluminum members. Nevertheless, this lubricant may have to be removed, e.g., cleaned, from the aluminum members after their formation in a die press. As a result, the manufacturing time of the heat exchanger may increase, as well as the cost of manufacturing the heat exchanger due to the need to provide a lubricant and to later remove the lubricant from the aluminum members.